The present invention relates to an optical element module including a light emitting element or a light receiving element to which an optical fiber terminal is opposed, and a method of assembling the optical element module.
As a related art optical element module, one disclosed for example in JP-A-2006-30813 is known. In FIG. 7, an optical element module 1 includes a light emitting device 2 and an enclosure 3. The optical element module 1 shown in FIG. 7 serves as a light emitting side in optical communications. The light emitting device 2 includes a substrate 4, a light emitting element 5 and an electronic component 6 mounted on the front surface of the substrate 4, and a is sealing resin 7 for sealing the light emitting element 5 and the electronic component 6. The enclosure 3 includes a main body 8 and a tube body 9 for inserting optical fibers to be integrated with the main body 8 and is formed into an illustrated shape.
At the rear part of the substrate 4 of the light emitting device 2 are formed a plurality of latching concave parts 10. In the concave parts 10 are engaged latching hook parts 11 farmed on the main body 8 of the enclosure 3. The light emitting device 2 is housed in contact with a stepped part 12 inside the main body 8. The light emitting device 2 is prevented from dropping by way of the fitting engagement of the concave parts 10 and the hook parts 11.
In this arrangement, when the light emitting device 2 is fitted into the main body 8, the light emitting element 5 is exposed through the sealing resin 7 from the opening at the tip of the tube body 9 of the enclosure 3. When an optical fiber terminal is inserted into the tube body 9, the inserted optical fiber terminal is opposed to the light emitting element 5. While not illustrated, the optical fiber terminal has a ferrule mounted thereon having an outer diameter matching the inner diameter of the tube body 9.
Fixing of the light emitting device 2 and the enclosure 3 is fitting engagement made through engagement of the concave parts 10 and the hook parts 11 and requires a fitting backlash from structural standpoint. Even when the light emitting device 2 and the enclosure 3 are fixed to each other, an axial misalignment corresponding to the fitting backlash remains therebetween.
The axial misalignment causes misalignment of an optical axis between an optical fiber and the light emitting element 5 with the optical fiber inserted in the tube body 9 of the enclosure 3. That is, optical losses are generated (the optical losses become greater as the axial misalignment increases).
In recent years, the increasing amount of information transfer volume and growing needs for real-time processing require a higher transmission speed of an optical signal. A smaller light receiving area of an optical fiber is needed to attain a higher transmission speed. The problem is that a reduced light receiving area of an optical fiber may not be supported by the optical element module 1 with higher optical losses.